Holder and switch for electric lamps



Och 1954 c. H. J. ANDERSON ETAL 2,692,319

HOLDER AND SWITCH FOR ELECTRIC LAMPS Filed Aug. 2, 1950 2 Sheets-Sheet 1IN VEN TORS C.H.J. ANDERSON J.H. F. VAN- WERD AGENT 0cb19, 1954 c. H. J-ANDERSON ETAL 2,692,310

HOLDER AND SWITCH FOR ELECTRIC LAMPS Filed Aug. 2, 1950 2 Sheets-Sheet 2o IN V EN TORS C.H.J. ANDERSON J.H.F. VAN WERD AGENT Patented Oct. 19,1954 UNITED STATES PATENT OFFICE HOLDER AND SWITCH FORELECTRIG LAMPStrustee Application August 2, 1950, Serial No. 177,264

Claims priority, application Netherlands August 11, 1949 2 Claims. (01.200-5139) This invention relates to a holder for securing tubularelectric lamps, more particularly lowpressure mercury-vapour dischargetubes, the holder consisting of a housing and a member rotatablysupported therein, and to a corresponding lamp cap for a tubularelectric lamp.

With a known holder of this type the rotatable member comprises at leasttwo movable contacts which are intended to be connected to an equalnumber of contacts on the lamp cap and to establish a connection with anequal number of fixed contacts in the housing, in accordance with theposition into which the member is moved. This rotation is normallyeffected by turning the lamp and in a known construction the member isprovided with a slot and the lamp cap with a ridge fitting in the slot.The purpose of this construction is to provide a large factor of safetyby practically preventing the movable contacts from being alive whenthere is no lamp in the holder.

The present invention relates to a holder of this type comprising onlyone movable contact, and has for its object to enhance the safety ofsuch holders and associated lamp caps and to simplify the construction.

It is based on the requirement that the construction of the holdershould be such as to permit rotation of the member practically only bymeans of the lamp cap, 1. e. that rotation of this member and making thecontact thereon alive by means of instruments or by hand should beprevented so far as is possible. Assuming this purpose to be obtained,it is not necessary to choose the location of this contact so as to bediflicult of access, for example in a slot. For the aforesaid reasonsthe use of a slot in the rotatable member is deemed objectionable, sinceit would permit of turning the member by means of various simpleinstruments, for example screw-drivers and coins.

According to the present invention, the rotatable member is providedwith a ridge on the side of the introduction of the lamp into theholder. Without using special tools, such as pincers, it is verydifiicult to turn the member by means of this ridge. The length of thisridge is preferably at least twice its height, in order that the coupleto be exerted thereon through a slot in the lamp cap may be dulytransmitted. This ridge is preferably formed by that part of the contactprovided on the rotatable member which is intended to engage the contactof the lamp cap. Of course, the ridge may alternatively be constitutedin part by this contact, whereas the remainder may consist of thematerial of the member itself.

The ends of the rid e may be rounded, thus fur-' ther impeding its beinggripped and facilitatingthe introduction of the lamp cap. If the lampholder is constructed in this manner, the associ-- ated cap may also besimplified. The known cap is provided with a ridge fitting in the slotof the,

since its slot weakens its side walls considerably.

If these side walls should break oil, the insertion of the lamp would nolonger be possible.

The cap according to the invention has a flat end-surface of insulatingmaterial, provided with a slot, on the bottom of which one contact isprovided.

The term flat end-surface is to be understood to mean that the width ofthe end-surface on either side of the slot is, on an average, at leastthree quarters of the width of the slot, but preferably exceeds thiswidth.

Ihe invention is furthermore based on the recognition of the fact thatthe shape of the movable contact (on the rotatable member) and of,

the slot may be chosen to be such that the contact on the lamp capengaging the slot practically cannot be touched and that the spacerequired for the slot is small, whilst the ridge fitting inthe slot isso small that itsbeing gripped is further impeded.

The end-surface, remote from the lamp, of the lamp cap accordingto theinvention is provided with a slot, the depth of which, measured from thetop of the contact, is at the most 5 mm., the

width of the slot being on an average, 4 mm. at

the most. Reference is made to the average width of the slot, since itmay be desirable to use a little greater width at the area of thecontact.

In the lampholder, the ridge, according to the invention, preferably hasa maximum height of 6 mm. and a maximum Width of 3 mm. A similar.

in detail with reference to the accompanying drawings in which:

Fig. 1 is a view of that side of the holder which is remote from theside of introduction of the.

lamp and which will be referred to as the back.

3 The rear wall of the holder and the rotatable member are broken away;I

Fig. 2 is a sectional view taken on the line II-II of Fig. 1;

Fig. 3 is a sectional view taken on the line III-III of Figs. 1 and 2;

Fig. 4 is a back view of the movable member and Figs. 5 and 6 are asectional view and an end view respectively of a lamp cap for use withthe holder shown in Figs. 1 to 4.

Figs. 6a and 6b are plan views from the left hand side of Fig. 5 of,respectively, the assembled lamp cap and only the cap portion.

Fig. 7 is a side view of the same lamp cap;

Fig. 8 is a side view of the holder as seen from a direction, oppositeto that, from which Fig. 1 was viewed.

The holder comprises a box I of insulatin material, for example mouldingmaterial. The lower portion of the box has an aperture 2, through whichone end of a lamp cap may pass (in Figs. 1, and 8 from above), the lampbeing moved parallel to itself. Around this aperture 2, the bottom 3 ofthe box carries an approximately horseshoe-shaped edge 4, the opening 5of which is up. This edge 4 (for the greater part shown in dotted linesin Fig. 2) constitutes a location for the movable member 6 which isurged into it by a helical spring I. The spring I rests at the back on aplate 8, which preferably also consists of insulating material andconstitutes the rear wall of the holder. At the top it is held under ahook-shaped part 9 of the box I and at the bottom by a flanged tube I0.

At the bottom end of the box I, an elevation II constitutes a location[2 for the lower end of the stationary contact I3. This contact is abent spring, the top I4 of which rests on the periphery of the movablemember 6 and the bottom end of which has a hook-shaped part I5 whichfits in the location l2. This part has an aperture through which ispassed a screw I6 with a nut II, which are housed between the box I andthe rear wall 8. The screw can be tightened through an aperture I8 inthe box, so that a conductor can be clamped between the nut II and thehookshaped part I5.

The movable member 6 (Figs. 2 and 4) comprises a disc of insulatingmoulding material, the front side of which is conically beveled at theedge at I9, so that it is urged into the centre of the location of theedge 4 under the action of spring I. However, it may also occupy anoblique position, if required by the position of the lamp relative tothe holder. A cavity 20 in which the spring I flts may be provided atthe back of the member 6. The front of this cavity has an elongatedaperture 2| through which are passed, from the rear side, twocrescent-shaped or semi-circular shaped contact plates 22, which jointlyform one contact extending forward from th front surface of therotatable member in the form of a ridge-like protuberance or ridge. Eachof these plates is integral with a strip 23, which extends at the backof the member 6 and forms a contact 24 at the periphery thereof. Thememher 6 is provided at its periphery with four grooves 25, two of whichaccommodate the strips 23. The plates 22 are held in the member by thespring I with the use of an insulating plate 26.

The lamp cap (see Figs. 5-7) to be used with these lamp holders consistsof a cap 2! placed on the tubular lamp, the cap having a circularaperture 28 with two elongated extensions 29 (Fig. 6b). In Fig. 6 thisaperture is indicated by broken lines.

A body 30 of insulating material is passed through these extensions withtwo lugs 3| and, after providing another insulating plate 32 at theinner side of the cap, it is secured by means of a washer 34 and aflanged tube 33. In this flanged tube, a supply wire 35 to an electrodeof the lamp is secured by soldering. The width of the aperture 28 ischosen to be such that suflicient insulation of the flanged tube 33 fromthe cap 21 is ensured.

The insulating body 3E3 has furthermore two lugs 36, which are formed bydividing the part, extending beyond the cap, for the greater part by aslot 31 (one side wall of which is shown in elevation in Fig. 5) and byproviding a circular groove 38 around the extension adjacent the cap.The bottom of this groove is circular and has two flattened parts (thebroken line in Fig. 6). The spacing A between these flattened parts isslightly smaller than the width B of the aperture 5 of the holder (Figs.6 and 1 respectively).

The operation of this holder will be described with respect to one endof the lamp; on the other side a similar holder is to be imagined.

The holder is mounted whilst the member 6 occupies the position shown inFig. 2. The contacts 22 cannot now be alive, since the end I4 of thestationary contact I3 does not engage one of the strips 23 (Fig. 4).

One of the ends of the lamp is inserted from' above into the holder andturned so that the body 30 passes through the aperture 5, theslot 3'!being directed such that the contacts 22 slide into it and engage theconductor 35 by way of the flanged tube 33. If the lamp is turned onequarter turn about the axis of the lamp, the slot 31 accommodates thecontact plates 22, causes the member 6 to turn, and one of the strips 23engages the end I4 of the stationary contact I3. This contact may now bealive. At the same time,

removal of the lamp is made impossible, since the insulating body 39forming part of the lamp is locked. A shift of the lamp parallel to itsaxis is made impossible, not only by the contacts 122 which now occupy atransverse position but also by that part of the body about which thegroove 38 is provided and which can no longer pass through the aperture5. A shift of the lamp in the direction of the axis is impossible, sincethe lugs 36 engage about the edge of the aperture 2 in the bottom of thebox I. r

The safety of this holder is ensured, since it is not possible to removethe lamp from the holder without first switching off the contacts 22.

It is possible to insert only one end of the lamp into the holder andsubsequently 'to ,turn' Although the lampholder and lamp cap describedare. particularly intended for use with low-pressure mercury-vapourdischarge tubes, so-called fluorescent lamps, they may also be used withtubular incandescent lamps having one 7 contact at each end.

What we claim is:

1. In combination, a lampholder for use with an elongated tubular lamphaving a given longitudinal axis and a terminal cap at each end of thelamp having a contact terminal thereon, said lamp holder comprising ahousing of insulating material, a fixed contact within the housing, amember rotatable within the housing, a flat, semi-circular-shapedcontact on said rotatable member on the side thereof facing the terminalcap and adapted to engage the terminal contact upon insertion of theterminal cap into the lampholder, said fiat, semi-circularshaped contactbeing adapted to rotate said rotatable member, and means operative uponrotation of said rotatable member with the terminal cap in engagementwith the contact thereon to effect an electrical connection between theterminal contact and the fixed contact.

2. In combination, a lampholder for use with an elongated tubular lamphaving a given longitudinal axis and a terminal cap at each end of thelamp having a contact terminal thereon, said lamp holder comprising ahousing of insulating material, a fixed contact within the housing, amember rotatable within the housing, a flat, semi-circular-shapedcontact on said rotatable member on the side thereof facing the terminalcap and adapted to engage the terminal contact upon insertion of theterminal cap into the lampholder, said flat, semi-circular-shapedcontact having a height dimension less than 6 mms. and a width dimensionless than 3 mms. and being adapted to rotate said rotatable member, andmeans operative upon rotation of said rotatable member with the terminalcan in engagement with the contact thereon to effect an electricalconnection between the terminal contact and the fixed contact.

References Cited in the file of this patent UNITED STATES PATENTS Number

